Alex Kentsis, MD, PhD, from Harvard Medical School in Boston, and colleagues used high-accuracy mass spectrometry proteomics to analyze proteins present in the urine of six patients with Kawasaki disease, six patients without Kawasaki disease, and three patients with Kawasaki disease who had completely responded to treatment.

The researchers identified 2,131 unique proteins. Of these, more than 190 were unique to patients with untreated Kawasaki disease and included markers of endothelial and myocardial cell injury and immune regulators. In particular, filamin C and meprin A were significantly elevated in both serum and urine of 236 patients with Kawasaki disease from two independent cohorts. In 107 patients with suspected Kawasaki disease, these two markers were able to diagnose the disease more accurately than current markers, with receiver operating characteristic areas under the curve of 0.98. In a mouse model of Kawasaki disease, meprin A was enriched in the coronary artery lesions.

"In all, urine proteome profiles revealed novel candidate molecular markers of Kawasaki disease, including filamin C and meprin A, that exhibit excellent diagnostic performance," Kentsis and colleagues conclude. "These disease markers may improve the diagnostic accuracy of clinical evaluations of children with suspected Kawasaki disease, lead to the identification of novel therapeutic targets, and allow the development of a biologic classification of Kawasaki disease."